This article attempts to address some of the common misunderstandings about applying the International Function Point Users Group counting rules. As long-term users, we often forget how much effort, study, learning, discussion, and analysis it took us to get where we are today. When we joined the Counting Practices Committee in 1989, we never dreamed how much time would be expended in that process. Of course, the function point rules and their definitions have become significantly better and easier to apply.

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How to Identify the Scope and Boundary of a Count

The counting scope is determined by the purpose of the count; it identifies
all of the systems, applications, and subsets of an application that will be
sized. The application boundary indicates the border between the application
being measured and external applications or the user domain.

When performing a function point count, how do you determine the scope and
application boundary when the system to be counted includes multiple applications?

The scope may include an entire project, but function points are counted
separately by application. Development projects and enhancement projects often
include more than a single application. In these cases, the multiple application
boundaries would be identified within the counting scope, but they would be
separately counted by application.

When performing a function point count, how do you determine the application
boundary when the system to be counted includes several platforms?

In a function point count, the application should be counted from the perspective
of the business solution versus the technical solution. The platforms are part
of the physical environment, not part of the functional requirements. As an
example, the application boundary of a client/server application consists of
all components that collectively meet the business requirements, regardless
of physical implementation or platform.

When performing a function point count, how do you determine the scope and
application boundary when the system to be counted includes a vendor package?
What should be counted when you purchase a package?

There are many potential counts relating to the purchase of a package. First,
when you shop for a package, you have a group of requirements that can and should
be sized; this is the functionality that you need. A potential vendor may already
have an application count, but do you care about the functionality that you
do not intend to use? Next, you should be interested in the enhancement project
count to make necessary changes to the package and satisfy interfacing requirements.
Finally, you need an application count to measure the functionality that will
be used after the enhancement.